Respiratory System

Question 1

Functions

Answer 1

Major: exchange of oxygen and carbon dioxide between an organism and its external environment
Minor: defending body against microorganisms, producing sounds for speaking, assisting in control of body fluid pH

Question 2

Cellular Respiration

Answer 2

We breathe to get oxygen needed to react with glucose in cellular respiration; cellular respiration produces carbon dioxide, water, ATP (energy molecules) - used to power energy-requiring processes in cells (growth, maintenance, building new molecules, etc.)

Question 3

Nose

Answer 3

Hairs in nose filter dust and particles, tissues that line nasal cavity moistens/warms air –> makes it easier for absorption of gases to occur (preferred entrance for air - inhalation)

Question 4

Mouth

Answer 4

Preferred exit for air - exhalation

Question 5

Pharynx

Answer 5

Pathway for food and air - two branches: trachea (air) and esophagus (food)

Question 6

Larynx

Answer 6

Passageway for air only, located in neck, covered by epiglottis to prevent choking, houses vocal cords (responsible for your voice)

Question 7

Trachea (Windpipe) and Bronchi (sing. Bronchus)

Answer 7

Both made of cartilage so they won’t collapse (trachea = long straight tube in chest cavity, bronchi = two smaller tubes divided from trachea)
Cells lining secrete mucus to trap foreign particles, mucus directed upward by cilia (long hair-like fibres) to epiglottis where mucus is swallowed and digested

Question 8

Bronchioles

Answer 8

Smaller tubes within lung divided from bronchi

Question 9

Alveoli

Answer 9

Clusters of air sacs at end of bronchioles, location of gas exchange, surrounded by capillaries, approx. 150 million per lung (increases surface area in lungs, increases rate of gas exchange), by time air reaches alveoli, warmed to 37°C and saturated in moisture (oxygen cannot diffuse across membrane unless dissolved in water)

Question 10

Characteristics of Gas Exchange Surfaces

Answer 10

1. High Surface Area - expanded alveoli would cover a tennis court
2. Short Diffusion Distance - alveoli are one cell thick
3. High Concentration Gradient - always new oxygen entering lungs, so concentration of oxygen is higher in lungs than in blood

Question 11

Movement of Air (Air Pressure)

Answer 11

Air always moves from high pressure to low pressure (more oxygen = higher pressure) –> there is an air pressure difference between the lungs and atmosphere

Question 12

Elevation and Air Pressure

Answer 12

Higher elevation = air is less dense (less oxygen –> more difficult to breathe)

Question 13

Inhalation

Answer 13

Rib (intercostal) muscles contract moving up and out –> diaphragm contracts moving down –> chest cavity increases in size –> air pressure decreases –> air drawn into lungs

Question 14

Exhalation

Answer 14

Rib cage and diaphragm relax –> returns to resting position (diaphragm moves up) –> decrease in cavity volume –> increase in air pressure –> air flows out of lungs

Question 15

Regulation of Breathing Movement

Answer 15

Chemical receptors in brain and arteries monitor oxygen & carbon dioxide levels in blood (when you don’t breathe - increased levels of carbon dioxide in blood (decreased pH), activating respiratory center of brain (medulla oblongata) ), sending signals to rib muscles and diaphragm to speed up or slow down rate of breath

Question 16

Pathways of Oxygen and Carbon Dioxide

Answer 16

Oxygen diffuses into cells
Carbon dioxide diffuses out of cells into blood, dissolves in plasma, and attaches to hemoglobin (as CO₂) OR travels in blood as bicarbonate ions (HCO₃) - balances pH

Question 17

Total Lung Capacity

Answer 17

Maximum volume of air that can be held in the lungs

Question 18

Tidal Volume

Answer 18

Amount of air that passes in or out of lungs with each breath

Question 19

Inspiratory Reserve Volume

Answer 19

Extra volume of air that can be inhaled during a deep breath

Question 20

Expiratory Reserve Volume

Answer 20

Extra volume of air that can be forcefully exhaled after the normal breath

Question 21

Vital Capacity

Answer 21

Maximum volume of air that can be moved into and out of the respiratory system

Question 22

Residual Volume

Answer 22

1-1.5L of air that always remains in your lungs to prevent them from collapsing

Question 23

Asthma

Answer 23

Chronic, long-term inflammation of lining of the bronchi and bronchioles - characterized by swelling, redness, overproduction of mucus (reduces airflow to lungs)
Symptoms: coughing, wheezing, tightness in chest, shortness of breath
Triggers: cigarette smoke, dust, pollen, physical exertion, cold air

Question 24

Chronic Obstructive Pulmonary Disease (COPD)

Answer 24

Long term disease where alveoli are permanently damaged (long history of lung problems)
Reduced surface area of respiratory membrane –> decrease in O₂ in blood, increase in CO₂ in tissues (leading to increased breathing rate & heart rate to compensate)

Question 25

Pneumonia

Answer 25

Infection of lung leading to inflamed alveoli, filled with fluid (commonly caused by bacteria Streptococcus pneumoniae) - symptom: difficulty breathing

Question 26

Emphysema

Answer 26

Respiratory membrane in alveoli is damaged or destroyed (usually from smoking)

Question 27

Cystic Fibrosis

Answer 27

Excess mucus production that is thick and sticky, clogging airways - genetic

Question 28

Pneumothorax

Answer 28

Collapsed lung caused by the introduction of air between the pleural membranes (e.g. rib puncture)

Question 29

Artificial Lungs

Answer 29

External to body - primary role is to remove CO₂ from body but some O₂ diffuses in as well

Question 30

Factors of Breathing Rate

Answer 30

Stress, fear, pain, exercise
Note: breathing is an involuntary action